Process for obtaining high grade sulphuric acid esters



Patented Aug. 23, 1938 UNITED STATES PROCESS FOR OBTAINING HIGH GRADE SULPHURIC ACID" ESTERS Konrad Cremer, Krefeld, Germany, assignor to Ohemische Fabrik Stockhausen 81 Cie., Krefeld, Germany, a German society No Drawing. Application April 20, 1936, Serial No. 75,409. In Germany July 12, 1928 7 Claims.

It is known that if oils and fats, their'fatty acids or mixtures of these substances are treated with concentrated sulphuric acid, mixed products are obtained which consist inpart'of sulphonated constituents, i. e. sulphuric acid esters, and

in part of unsulphonated constituents.

According to one known method which has been proposed, for example, the sulphonated products are obtained by treating themixtures with solvents.

7 According to the present'invention, the reaction mixtures obtained are worked-up in a very simple and inexpensive manner by the addition of compounds which are capable of converting the sulphonated fractions into compounds which remain in solution under the given conditions and the non-sulphonated fractions into compounds which are insoluble under the given conditions. The separation is thus effected by fractional precipitation.

As separating agents may be used oxides, hydroxides or salts of the alkaline earth or heavy metals, for example slaked lime, calcium chloride, zinc carbonate, chromium hydroxide, ferric chloride, lead carbonate, copper sulphate, mercuric chloride and so forth.

The quantity of the compounds of the alkaline earth or heavy metalsto be added depends on the kind of reaction mixture to be worked up and it may vary within considerable limits. Too great an excess of the precipitating agent which might lead to separation of fatty sulphuric acid esters should, of course, be avoided.

In carrying out the invention the procedure may, for example, be as follows:-

The sulphonation mixture is freed from excess of sulphuric acid by washing with water or a salt solution, and, after removal of the liquid containing the acid, the separating agent is added. The separating agent may be added to the reaction mixture before or after neutralizing the reaction mixture for example with alkali. Thus, one may proceed for example by first neutralizing wholly or in part the reaction mixture which has been freed from excess of sulphuric acid and only then adding the separating agent. In many cases, however, it has been found advantageous to dilute the reaction mixture with water. By this means the separation of the salts of the unsulphonated products is facilitated. The precipitated soaps of the alkaline earth or heavy metals can be easily and completely separated from the salts of the fatty sulphuric acid esters which remain in solution by measures such as filtering or centrifuging. The esters can be obtained from Cal the solution by simple measures such as, for example, separation by'means of acids, salting out and so forth.

The process may be employed in general for working-up reaction mixtures such as are obtained in the treatment of oils, fat, fatty acids or mixtures of the same with sulphuric acid or agents having a similar action, for example monohydrate or oleum. It can also be employed for example for working up ordinary Turkey red oils and products. resembling the Turkey red oils, for products of the character of the so-called monopole-soap (see German specification No. 113,433), for the so-called highly sulphonated oils and fats such as are described for example in" the Germanspecification No. 561,715.

The purified sulphuric acid esters obtained in accordance with the methods of the present invention are distinguished from the products which can be obtained by the known'methods by a great improvement in their properties, particularlyasregards their stability to acids, salts, al-

kalies, chlorine solutions and so forth as well as by a considerably increased wetting power.

Example 1 kg. of Turkey red oil (commercial 37,5% fatty acid content) are treated while being gently heated and stirred with 10 kg. of slaked lime.

In order to facilitate the deposition of the calcontent of fat. The improvement in the product will be seen from the fact, among others, that the content-of sulphuric acid combined in esterlike form has risen from about 8% in the starting material to about 14%. An improvement in the properties of the material takes place at the same time. Thus, the stability to acid, for example, rises from 8 to 44.

Example 2 300 kg. of a sulphonated oil containing about 17% of sulphuric acid combined in ester-like form and a fat content of about 37% are diluted with the same amount of water and a calcium chloride solution which has been obtained by dissolving 20 kg. of CaClz in as small a quantity of water as possible is gradually added. The mate- III rial is worked up in the manner indicated in Example 1. The content of the purified product which is obtained of sulphuric acid combined in ester-like form rose to about 27%. The stability to acid amounted to about 4000. as compared with about 500 of the starting material.

Example 3 300 kg. of a reaction mixture which was ob tained by sulphonating olein in the cold with concentrated sulphuric acid and washing out the excess acid with Glaubers salt solution were diluted with double the quantity of water. 70 kg. of zinc carbonate were gradually added to the solution. The material was worked up in the same manner as in Example 1. By the'purifying process the stability to acid increased from about 1200 to over 7000.

Example 4 300 kg. of a highly sulphonated oil containing about 18,1% of sulphuric acid combined in esterlike form and having a fatty acid content of about 38% are treated with soda lye to give a neutral reaction with phenolphthalein. After dilution with 350 kg. water a solution of 46 kg. lead acetate in 46 kg. of water are added and the mixture stirred. The material is worked up in the same manner as in Example 1. The purified product contains about 26,9% of sulphuric acid combined in ester-like form.

I claim:

1. In a process for obtaining high grade sulphuric acid esters from reaction mixtures produced by sulphonating oils, fats, their fatty acids or mixtures thereof, the improvement comprising the steps of freeing from the reaction mixture resulting from the sulphonation process, the excess sulphuric acid; treating the reaction mixture, freed of the excess sulphuric acid, with a separating agent consisting of a compound of a metal selected from the group consisting of alkaline earth and heavy metals, in aqueous solution, to convert the sulphuric acid esters into water soluble salts and the non-sulphonated fractions into insoluble salts, the acid separating agent being of such concentration as to retain the salts of the sulphuric acid esters in solution but will precipitate out the salts of the non-sulphonated fractions; separating the precipitated salts of the non-sulphonated fractions from the solution of the salts of the sulphuric acid esters; and then separating the refined sulphuric acid esters from the solution containing the same.

2. A process, as claimed in claim 1, wherein an oxide of a metal selected from the group consisting of alkaline earth and heavy metals is used as separating agent.

3. A process, as claimed in claim 1, wherein a hydroxide of a metal selected from the group consisting of alkaline earth and heavy metals is used as separating agent.

4. A process, as claimed in claim 1, wherein a salt of a metal selected from the group consisting of alkaline earth and heavy metals is used as separating agent.

5. A process, as claimed in claim 1, wherein the reaction mixture resulting from the sulphonation process and freed of the excess sulphuric acid is treated with a neutralizing agent before addition of the separating agent.

6. A process, as claimed in claim 1, wherein the reaction mixture resulting from the sulphonation process and freed of the excess sulphuric acid is diluted with water, to facilitate the separation of the salts of the non-sulphonated fractions.

'7. A process, as claimedin claim 1, wherein the reaction mixture resulting from the sulphonation process and freed of the excess sulphuric acid, is treated with a neutralizing agent and then diluted with water, before addition of the separating agent. I

- KONRAD CREMER. 

